Catherine Venusto, 45, admitted to using password information obtained while employed as a secretary for the Northwestern Lehigh School District to log onto the computer system on multiple occasions, according to authorities.

Using district superintendent Dr. Mary Anne Wright's sign-on and password, she changed a failing grade for her daughter to a medical exception in 2010 and bumped up a grade of 98 to a 99 for her son in February, authorities said.

"At the time, I didn't quite have a grasp of the scope of what happened, but I was immediately concerned for protected information," Wright said. "We shut down the system within three hours of learning there was a potential problem."

As a secretary, Venusto's duties included creating sign-in and passwords for Wright and several other employees, the Morning Call reported.

The release said an investigation found Venusto logged into the district's computer system more than 100 times using Wright's password.

Venusto used three different Internet-provider addresses, one from her home, the East Penn School District and another associated with QVC, to log onto the system, the news release said.

"We deeply regret this incident and that this unauthorized access occurred, and we sincerely regret any inconvenience this may cause," Wright said in a statement posted on the district's website.

Holman said no evidence was found suggesting employee personal information was compromised or used for illegal purposes. She told NBC News that the grades for Venusto's children were the only ones changed.